Snowmobiles are popular recreational and utilitarian vehicles for use in snowy conditions. Snowmobiles are driven for variety of purposes and under a variety of conditions. For example, snowmobiles are used for touring, racing, and rescue operations in remote areas. The conditions in which snowmobiles are operated can significantly impact the performance of the snowmobile. For instance, the snow conditions may be light and powdery or conversely, it may be hard packed.
Typical snowmobiles include, inter alia, a pair of skis for steering, a seat, handlebars, and an endless track for propulsion mounted to a central chassis. The pair of skis serve to facilitate steering as well as to provide floatation of the front of the snowmobile over the snow in which it is operated. The ski stance of a snowmobile refers to the distance separating the left and right ski as measured from a predetermined location on each ski. The ski stance significantly impacts the driving performance and handling of the snowmobile.
Driving performance of the snowmobile is of momentous importance to snowmobile enthusiasts. Characteristics such as, steerability, maneuverability, floatation, and side-hilling capability contribute to the ride characteristics of a snowmobile. Particular characteristics become important when the snowmobile is driven in certain terrain or snow conditions.
Currently, snowmobiles are marketed to accommodate two general types of riding; trail and mountain. In general, trail riding snowmobiles are provided with a widened ski stance, which may be as great as 48 inches, the maximum permitted by the Snowmobile Safety Certification Committee (SSCC). Conversely, mountain snowmobiles are provided with a relatively narrow ski stance.
Mountain riding, that is, the absence of groomed trails, requires good floatation and side-hilling characteristics. Floatation refers to the snowmobile's ability to be propelled over powder snow. Side-hilling capabilities are of significant importance in mountain riding, where riders traverse hillsides in a switchback fashion. Side-hilling capability ensures the snowmobile will not slip when each ski dominates as the snowmobile switches back and forth. A relatively narrow ski stance is preferable to engage the maximum amount of snow under the skis during the tilting that occurs when driving in a switchback fashion.
In contrast, groomed trail riding exerts different demands in terms of performance. Groomed trails generally provide a solid packed base with an overlay of loose powder. Since the bottom surfaces of each ski remain in contact with the ground at nearly all times, stability during turning or cornering requires a relatively wide ski stance. Typically, the maximum ski stance is about 48 inches.
Since trail and mountain riding require differing ski stances, snowmobile manufacturers market distinct models suited for either type of ride by providing snowmobiles with relatively narrow or wide ski stances. This choice may prove problematic for consumers, who have to choose between the two options. It is particularly problematic where a consumer desires to use the snowmobile for both trail and mountain riding. In this instance, the consumer may be required to purchase two separate snowmobiles to achieve optimal performance under both riding conditions.
It would be desirable therefore, to provide a snowmobile with an adjustable ski stance so that owners may make adjustments according to the particular type of riding they intend to undertake. That is, the stance may be widened for trail conditions and narrowed for off-trail riding. There have been a number of developments to allow such versatility in a single snowmobile. For example, U.S. Publication No. 03/0019676 describes the use of specialized rotatable spindles with offset (relative to the centerline of the axis of rotation) means for connecting the spindle to the ski. The ski stance is adjusted by unbolting the top portion of the spindle from the steering arm and the bottom portion from the ski, rotating the spindle 180°, and rebolting the rotated spindle to the steering frame and ski. While such a design allows for ski stance adjustment, the process is cumbersome, requires a variety of tools, and is time consuming.
Other methods involve the use of bushings and separate spacers to couple the spindle to the ski and offset the ski relative to a fixed point on the frame of the snowmobile. These designs allow for adjustment without the requirement of complete disassembly of the ski, however, multiple parts make the process time consuming and cumbersome. There remains therefore, a need for quickly and conveniently adjusting the ski stance on a snowmobile.